Dozens of tourists robbed on trail to Rio's famous Christ the Redeemer statue

Rising violence in Rio de Janeiro has reduced tourism, costing NZ$296m in lost revenue in 2017.

Dozens of tourists hiking toward the famous Christ the Redeemer statue in Rio de Janeiro were held at gunpoint for up to two hours in a mass robbery that could mark an early test for anti-crime crackdowns promised by Brazil's new president.

Police said Friday that at least three assailants carrying knives and a gun set up the ambush on the trail, which cuts through a dense forest that borders a slum on the outskirts of the city and has been the site of numerous muggings.

In total, more than 30 people were robbed Thursday - about half foreigners from Asia, Europe and elsewhere in South America - as the thieves took hostages and waited for more tourists to arrive.

But the incident dealt another blow to Rio's increasingly lawless reputation and came just days after the inauguration of President Jair Bolsonaro, a former army captain who made battling crime a centrepiece of his campaign.

Bolsonaro's promises to crack down on crime by arming average citizens has proved popular among voters, though experts warn it could increase unrest.

In Rio, authorities are facing a record crime wave that has claimed tens of thousands of lives and damaged the city's critical tourism industry. Tourists travelling with cameras and smartphones have become easy targets, particularly on the popular route to the Redeemer statue.

"For a year and a half, there have been a large number of cases on this trail," Valéria Aragão, chief of Rio's tourism police, told reporters. The tourism police have conducted joint operations to combat the muggings in the area.

The city lost over US$200 million (NZ$296m) in tourism revenue in 2017 due to crime and violence, according to the National Confederation of Commerce of Goods, Services and Tourism.

Rio saw a respite in homicides at the start of the decade. But a gruelling recession dried up police budgets and left areas that were once heavily policed to the mercy of warring gangs.

Last February, Brazil's then president, Michel Temer, declared a state of emergency and deployed the military to occupy the streets of Rio.

In his inauguration speech on Tuesday, Bolsonaro said Brazil was entering a new era.

"Our concern will be the safety of good people, a guarantee of property rights and of the right to legitimate defence," he said.